Thousands of protesters packed parks, lined roadways and filled courthouse steps across Long Island and in New York City on Saturday, joining a national mobilization against the policies of President Donald Trump's administration. 

The rallies were among hundreds of "No Kings" protests held in American cities as a military parade celebrated the 250th birthday of the U.S. Army in Washington, D.C. and coincided with Trump's 79th birthday.

From Brooklyn to the East End, protestors took to the streets under ponchos and umbrellas to voice their frustrations, fueled by what they said is an abuse of power by the president, as well as the recent crackdown on immigrants in the country illegally, federal spending cuts that could target programs like Medicaid and opposition to using government funds on the parade. The military parade is estimated to cost $45 million, according to the Associated Press.

In Mineola, an estimated 2,000 protesters wielding signs and American flags descended on the grounds of the Nassau County Courthouse. Outside Heckscher Park in Huntington, around 2,000 more waved flags as chants of “USA” and “This is what democracy looks like” echoed down the winding road.

Thousands more gathered at similar demonstrations outside the local office of Rep. Andrew Garbarino (R-Bayport) in Patchogue, at the Suffolk County Supreme Court in Riverhead and as far east as Orient and East Hampton.

In Manhattan, more than 10,000 people crammed sidewalks and roadways, leading the NYPD to bar vehicular traffic for several hours on Fifth Avenue from 42nd to 23rd streets to accommodate the crowds.

Police departments in both Nassau and Suffolk had said they were prepared for the demonstrations. The protests on Long Island were largely peaceful Saturday, with no arrests reported in either county. At rallies across Long Island, passing cars honked their horns in support while a few detractors waved Trump flags as they passed.

In Mineola, Assemb. Phil Ramos rebuked the military celebration held by Trump in Washington D.C. as he said local communities are "under siege."

"While mothers in Brentwood are praying that their children make it home safely, while ICE agents tear fathers from their families without warrants, Donald Trump is having a birthday party — let that sink in," Ramos said.

Lt. Gov. Antonio Delgado said Saturday's series of rallies are a reminder "we didn't like being ruled by a king or bloodline."

"We remember that we didn't sign up for a president who would commandeer the National Guard on Americans," Delgado said.

Republican officials throughout the state denounced the protests, shutting down the notion that Trump is a king or dictator.

More than 53% of voters in Nassau and Suffolk counties voted for Trump in 2024, and in winning Nassau he became the first Republican presidential candidate to take the county since 1988, Newsday has reported.

"The American people choose our leaders at the ballot box, not in the streets with juvenile chants and temper tantrums," David Laska, director of communications for the New York State Republican Party, said in an email Saturday.

"While they're out blocking traffic, the rest of us will be celebrating America and honoring our military."

Suffolk County GOP chairman Jesse Garcia criticized the timing of the protests, which fell on Flag Day.

He accused demonstrators of protesting against immigration policies aimed at safety.

"They’re putting the interests of illegal criminal migrants ahead of American citizens,” he said. "This is the same group of people that support trampling on Old Glory and also would rather wave the flags of countries criminal illegal migrants are fleeing, but don’t want to go back to.”

Immigration was a key factor in the demonstrations.

Rachel Klein, founder of Engage Long Island and an organizer of the Mineola rally, said a ramp up of immigration efforts across the country has stoked a climate of fear, including on Long Island.

"There are people in Brentwood and Westbury and Huntington Station and Glen Cove who are afraid to leave their homes right now," she said. "We can't function as as a society like this."

Saturday’s rally in Patchogue was the largest of several protests that have occurred at the site in front of Garbarino’s office in recent months.

Ingris Agustin of Medford held an American flag upside down as she chanted along to, "no hate, no fear, immigrants are welcome here."

A first-generation American whose parents are from Guatemala, Agustin said she felt it was important to stand up for people who can't advocate for themselves.

"It's just very unjust what's happening now," she said. "In another universe, I could be the one being dragged away."

Navy veteran Larry Andria of Remsenburg, who served from 1967-71, said he believes there should be pathways to citizenship for undocumented immigrants.

He said he supports deporting criminals, but not people with lesser infractions like a speeding ticket.

"You need to be more specific on how you go about removing people and have a little compassion for it," he said, adding that he disapproved of the military parade and its cost to taxpayers.

"People are out without jobs now because of DOGE," Andria said. "It's just not right."

On the East End, many stood in solidarity with immigrant neighbors who they said are fearful about recent immigration enforcement efforts.

“I’m here to support those who might not be able to have a voice,” said Erica Blanco, 30, of Hampton Bays. “I fear for the future of others and I want to make sure I’m saying what I can to help. Even if it’s just here.”

In New York City, protests were held in Forest Hills, outside Grand Central Terminal, at Grand Army Plaza in Brooklyn and at Columbia University.

Rita Harris, of Boston, and her husband, holding American flags, attended the Brooklyn march while visiting their adult son, who lives near the protest site. 

 "He needs to hear us," Harris, 77, said of Trump. "The people need to have a voice in what's going on in Washington."

Harris said the parade is a "gross use" of taxpayer money. "I think it's nothing but a power trip for him. The cost, to the armed services, it's ridiculous."

Heather Trobe, a union organizer from Brooklyn, marched with her four-year-old son Lucca, and said she was “disturbed” by deportations and ICE detentions, which she said is a threat to democracy.

“I want Trump to know that America is not gonna go quietly,” said Trobe, 41. “For people who are worried about the state of our democracy to know that they're not alone and there's endless solidarity out there.”